Networks with applications that, in general, rely on high levels of precision to implement one or more functions typically use synchronization protocols such as network timing protocol (NTP) or precision timing protocol (PTP) in order to provide time synchronization for the elements (nodes) within the network. NTP and PTP are both packet-based synchronization methods that transfer time and frequency references using packets containing time-stamps between elements in the network. The time-stamps, in general, are associated with the time-of-arrival and time-of-departure of the packets, which the network elements use to perform synchronization.
The key difference between NTP and PTP is the level(s) of precision obtainable between the two protocols. For example, NTP is generally used for general timing applications and is capable of providing timing synchronization on the order of (several) milliseconds. PTP (as specified in IEEE-1588v2), on the other hand, is generally used for applications that require high levels of precision (e.g., such as industrial automation networks, testing and measurement networks, telecommunications networks, etc.) and is capable of providing timing synchronization on the order of nanoseconds.
A typical PTP deployment generally involves the use of a PTP master, PTP slave, PTP boundary clock (BC) and/or PTP grandmaster to provide timing synchronization. The PTP master provides the reference point (e.g., in the form of time-stamps) that one or more PTP slaves connected to the PTP master utilize in order to perform synchronization. A PTP master that is synchronized to a primary reference clock (PRC) (such as an atomic clock, GPS, etc.) is referred to generally as a PTP grandmaster and is typically used as the root timing reference. A PTP BC, in general, is a device that has both slave and master functions and may be used to transfer time in a relay fashion. For example, the BC may act as a slave clock to a master clock and also as a master clock to one or more slaves in the network.
To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one embodiment may be beneficially utilized on other embodiments without specific recitation.